dc.contributor.author	Waajen, Annemiek C.
dc.contributor.author	Heinz, Jacob
dc.contributor.author	Airo, Alessandro
dc.contributor.author	Schulze-Makuch, Dirk
dc.date.accessioned	2020-08-28T13:47:12Z
dc.date.available	2020-08-28T13:47:12Z
dc.date.issued	2020-07-07
dc.date.updated	2020-07-08T03:11:44Z
dc.description.abstract	Microorganisms living in sub-zero environments can benefit from the presence of dissolved salts, as they significantly increase the temperature range of liquid water by lowering the freezing point. However, high concentrations of salts can reduce microbial growth and survival, and can evoke a physiological stress response. It remains poorly understood how the physicochemical parameters of brines (e.g. water activity, ionic strength, solubility and hydration shell strength between the ions and the surrounding water molecules) influence the survival of microorganisms. We used the cryo− and halotolerant bacterial strain Planococcus halocryophilus as a model organism to evaluate the degree of stress different salts assert. Cells were incubated in liquid media at −15°C containing single salts at eutectic concentrations (CaCl2, LiCl, LiI, MgBr2, MgCl2, NaBr, NaCl, NaClO4 and NaI). Four of these salts (LiCl, LiI, MgBr2 and NaClO4) were also investigated at concentrations with a low water activity (0.635) and, separately, with a high ionic strength (8 mol/L). Water activity of all solutions was measured at −15°C. This is the first time that water activity has been measured for such a large number of liquid salt solutions at constant sub-zero temperatures (−15°C). Colony-Forming Unit (CFU) counts show that the survival of P. halocryophilus has a negative correlation with the salt concentration, molecular weight of the anion and anion radius; and a positive correlation with the water activity and anions’ hydration shell strength. The survival of P. halocryophilus did not show a significant correlation with the ionic strength, the molecular weight of the cation, the hydrated and unhydrated cation and hydrated anion radius, and the cations’ hydration bond length. Thus, the water activity, salt concentration and anion parameters play the largest role in the survival of P. halocryophilus in concentrated brines. These findings improve our understanding of the limitations of microbial life in saline environments, which provides a basis for better evaluation of the habitability of extraterrestrial environments such as Martian cryobrines.	en
dc.description.sponsorship	EC/FP7/339231/EU/Habitability of Martian Environments: Exploring the Physiological and Environmental Limits of Life/HOME	en
dc.description.sponsorship	DFG, 414044773, Open Access Publizieren 2019 - 2020 / Technische Universität Berlin	en
dc.identifier.eissn	1664-302X
dc.identifier.uri	https://depositonce.tu-berlin.de/handle/11303/11619
dc.identifier.uri	http://dx.doi.org/10.14279/depositonce-10506
dc.language.iso	en	en
dc.rights.uri	https://creativecommons.org/licenses/by/4.0/	en
dc.subject.ddc	570 Biowissenschaften; Biologie	de
dc.subject.other	Planococcus halocryophilus	en
dc.subject.other	salt stress	en
dc.subject.other	water activity	en
dc.subject.other	ionic strength	en
dc.subject.other	survival	en
dc.title	Physicochemical Salt Solution Parameters Limit the Survival of Planococcus halocryophilus in Martian Cryobrines	en
dc.type	Article	en
dc.type.version	publishedVersion	en
dcterms.bibliographicCitation.articlenumber	1284	en
dcterms.bibliographicCitation.doi	10.3389/fmicb.2020.01284	en
dcterms.bibliographicCitation.journaltitle	Frontiers in Microbiology	en
dcterms.bibliographicCitation.originalpublishername	Frontiers Media S.A.	en
dcterms.bibliographicCitation.originalpublisherplace	Lausanne	en
dcterms.bibliographicCitation.volume	11	en
tub.accessrights.dnb	free	en
tub.affiliation	Fak. 2 Mathematik und Naturwissenschaften::Zentrum für Astronomie und Astrophysik	de
tub.affiliation.faculty	Fak. 2 Mathematik und Naturwissenschaften	de
tub.affiliation.institute	Zentrum für Astronomie und Astrophysik	de
tub.publisher.universityorinstitution	Technische Universität Berlin	en

Physicochemical Salt Solution Parameters Limit the Survival of Planococcus halocryophilus in Martian Cryobrines

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